Pigment preparations based on diketopyrrolopyrrole pigments for the undistorted pigmentation of partially crystalline plastics

ABSTRACT

A pigment preparation comprising a) at least one diketopyrrolopyrrole pigment of the formula (V) as a base pigment and b) at least one pigment dispersing agent based on sulphonated diketopyrrolopyrrole derivatives and the use thereof for the undistorted coloration of plastics

This invention relates to pigment preparations based ondiketopyrrolopyrrole pigments with diketopyrrolopyrrole-derived pigmentdispersants for coloration of macromolecular material, particularly forwarpage-free pigmentation of partly crystalline plastics, especiallypolyolefins.

The coloration of partly crystalline plastics with organic pigmentsfrequently gives rise to warpage or distortion phenomena. Thepigmentation of large-volume injection moldings, especially thosecomposed of polyethylene, leads to deformation, shrinkage and cracking(internal stresses), rendering the colored articles unusable, dependingon the field of application. Bottle crates, for example, are likely tobecome unstackable by loss of shape.

These disadvantages relate to the majority of organic pigments, whereasinorganic pigments and a minority of organic pigments behave neutrally.It is believed that pigments act as nucleation sites during thesolidification of the polymer melt and thus lead to a polymer which isprone to warp/distort.

As well as providing warpage-free colorations, pigments used forcoloration of plastics have to meet high performance requirements aspigments, such as good dispersibility, high color strength, clean huesof high chroma, high thermal fastness, good resistance to bleeding andgood light and weather fastnesses. It would also be desirable forpigments to be useful not just for one system but ideally universally.Thus, pigments should also be suitable for non-partly-crystallineplastics and also for coloration of other macromolecular organicmaterials and be useful in, for example, coating or printing systems,where still other requirements have to be met, such as for example lowviscosity for the grind formulations or for the ready-produced printingand coating colors, good flocculation resistance, solvent andovercoating fastnesses, high luster and, in the case of metalliccoatings, high transparency.

Various methods have already been proposed to counteract the warpageproblem. Warpage-free pigments are obtained according to U.S. Pat. No.4,880,472 through silica- or alumina-coated pigments, according to EP 0296 107 through ethylcellulose-coated pigments, according to EP 0 466646 through pigments coated with polar polymers, according to DE 42 14868 through ternary pigment preparations comprising a base pigment, asulfonic acid and alkali metal sulfonate group modified organic pigmentand a polymeric ammonium salt, according to DE 43 13 090 through organicpigments which have been exposed to a low temperature plasma, accordingto EP 659 840 by coating the pigment with phosphate complexes andaccording to EP 952 183 through use of diketopyrrolopyrroles havinglong-chain substituents.

DE 199 58 181 discloses3,6-bis-([1,1′-biphenyl]-4-yl)-2,5-dihydro-pyrrolo(3,4-c)pyrrole-1,4-dioneswhich are substituted by sulfonamide groups and are useful as pigmentdispersants.

However, these methods do not always meet current requirements withregard to the performance characteristics described above. The presentinvention has for its object to find new ways to achieve warpage-freecoloration of partly crystalline plastics with diketopyrrolopyrrolepigments.

We have found that this object is surprisingly achieved by a novelpigment preparation described hereinbelow.

The present invention accordingly provides a pigment preparationcomprising

-   -   a) at least one diketopyrrolopyrrole pigment of the formula (V)        as a base pigment,

-   -   where    -   R²⁰, R²¹, R²² and R²³ are independently hydrogen, halogen, such        as for example chlorine or bromine, C₁–C₄-alkyl, such as for        example methyl, ethyl or tert-butyl, C₁–C₄-alkoxy, such as for        example methoxy, cyano or phenyl;    -   and    -   b) at least one pigment dispersant of the formula (I),

-   -   where    -   R³¹ is a radical of the formula (VI), (VIII) or (IX),    -   R³² is a radical of the formula (VII),    -   s or t are a number from 0.1 to 4.0

-   n is a number from 0 to 2, with the proviso that n is 0 when R³¹ is    a radical of the formula (VIII) or (IX),-   E⁺ is H⁺ or the equivalent M^(m+)/m of a metal cation M^(m+) from    the 1st to 5th main group or from the 1st or 2nd or from the 4th to    8th transition group of the periodic table of chemical elements, m    being one of 1, 2 or 3, such as for example Li¹⁺, Na¹⁺, K¹⁺, Mg²⁺,    Ca²⁺, Sr²⁺, Ba²⁺, Mn²⁺, Cu²⁺, Ni²⁺, Co²⁺, Zn²⁺, Fe²⁺, Al³⁺, Cr³⁺ or    Fe³⁺; an ammonium ion N⁺R⁹R¹⁰R¹¹R¹², where the substituents R⁹, R¹⁰,    R¹¹ and R¹² are each independently a hydrogen atom, C₁–C₃₀-alkyl,    C₂–C₃₀-alkenyl, C₅–C₃₀-cycloalkyl, phenyl, (C₁–C₈)-alkylphenyl,    (C₁–C₄)-alkylenephenyl, for example benzyl, or a (poly)alkyleneoxy    group of the formula —[CH(R⁸⁰)—CH(R⁸⁰)—O]_(k)—H, where k is a number    from 1 to 30 and the two R⁸⁰ radicals are independently hydrogen,    C₁–C₄-alkyl or, when k is >1, a combination thereof;    -   and wherein R⁹, R¹⁰, R¹¹ and/or R¹² alkyl, alkenyl, cycloalkyl,        phenyl or alkylphenyl may each be substituted by amino, hydroxyl        and/or carboxyl; or where the substituents R⁹ and R¹⁰ may        combine with the quaternary nitrogen atom to form a five-, six-        or seven-membered saturated ring system which if appropriate        contains still further heteroatoms selected from the group        consisting of O, S and N, for example of the pyrrolidone,        imidazolidine, hexamethyleneimine, piperidine, piperazine or        morpholine type;    -   or where the substituents R⁹, R¹⁰ and R¹¹ may combine with the        quaternary nitrogen atom to form a five-, six- or seven-membered        aromatic ring system which if appropriate contains still further        heteroatoms selected from the group consisting of O, S and N and        which has if appropriate additional rings fused onto it, for        example of the pyrrole, imidazole, pyridine, picoline, pyrazine,        quinoline or isoquinoline type;        or wherein E⁺ defines an ammonium ion of the formula (Ic)

where

-   R¹⁵, R¹⁶, R¹⁷ and R¹⁸ are independently hydrogen or a    (poly)alkyleneoxy group of the formula —[CH(R⁸⁰)—CH(R⁸⁰)O]_(k)—H,    where k is a number from 1 to 30 and the two R⁸⁰ radicals are    independently hydrogen, C₁–C₄-alkyl or, when k>1, a combination    thereof;-   q is a number from 1 to 10, preferably 1, 2, 3, 4 or 5;-   p is a number from 1 to 5, subject to the proviso that p≦q+1;-   T is a branched or unbranched C₂–C₆-alkylene radical; or where T    when q is >1 may also be a combination of branched or unbranched    C₂–C₆-alkylene radicals;-   Z¹ and Z² are the same or different and are hydrogen or C₁–C₃₀-alkyl    or C₁–C₃₀-alkenyl radicals which are linear or branched and    unsubstituted or halogen, hydroxyl, hydroxycarbonyl or    C₁–C₆-alkoxy-substituted, wherein the alkenyl radical may be singly    or multiply unsaturated, with the proviso that Z¹ and Z² are not    both hydrogen;    and-   Q is a radical of a diketopyrrolopyrrole compound of the formula    (Ia)

where R²⁴, R²⁵, R²⁶ and R²⁷ are independently hydrogen, halogen, such asfor example chlorine or bromine, (C₁–C₄)-alkyl, such as for examplemethyl, ethyl or tert-butyl, (C₁–C₄)-alkoxy, such as for examplemethoxy, or cyano.

Particular interest pertains to pigment dispersants of the formula (I)where s or t are 0.2 to 3.0 and n is 0 to 0.5, especially pigmentdispersants of the formula (I) where s or t is 0.5 to 2.5 and n is 0 to0.2.

Particular interest further pertains to pigment dispersants of theformula (I) where

-   Z¹ and Z² are the same or different and are each C₂–C₁₆-alkyl,-   R²⁴ and R²⁶ are each hydrogen and-   R²⁵ and R²⁷ are each hydrogen, methyl, tert-butyl, chlorine or    cyano.

The pigment dispersants of the present invention can be prepared byprocesses known to one skilled in the art.

By base pigment are meant diketopyrrolopyrrole pigments or mixtures ofpigments comprising at least one diketopyrrolpyrrole pigment, which mayalso be present as conventional pigment preparations.

Particular interest pertains to diketopyrrolopyrrole base pigments ofthe formula (V) where

-   R²¹ and R²³ are both hydrogen and-   R²⁰ and R²² are the same or different and each hydrogen, methyl,    tert-butyl, chlorine, cyano or phenyl.

Preferred diketopyrrolopyrrole pigments useful as base pigments are forexample C.I. Pigment Orange 71, 73, 81 and C.I. Pigment Red 254, 255,264, 270, 272.

When the base pigment, as well as the diketopyrrolopyrrole pigment,comprises other pigments, these other pigments can be those listed inColour Index International Fourth Edition Online.

The pigment preparations of the present invention, as well as the basepigment a) and the pigment dispersant b), may further comprise c)auxiliaries, such as for example surfactants, pigmentary andnonpigmentary dispersants, fillers, standardizers, resins, waxes,defoamers, antidust agents, extenders, shading colorants, preservatives,dryness retarders, rheology control additives, wetting agents,antioxidants, UV absorbers, light stabilizers or a combination thereof.

Preferred pigment preparations in the present invention consistessentially of

-   a) 50% to 99.9% by weight, preferably 55% to 99.5% by weight and    more preferably 60% to 99% by weight of at least one base pigment    according to a),-   b) 0.1% to 25% by weight, preferably 0.5% to 20% by weight and more    preferably 1% to 15% by weight of at least one, preferably one or    two, pigment dispersant according to b),-   c) 0% to 25% by weight and preferably 0% to 15% by weight of    auxiliaries, the fractions of the respective components being based    on the total weight of the preparation (100% by weight).

Useful surfactants include anionic or anion-active, cationic orcation-active and nonionic substances or mixtures of these agents.

Examples of suitable anion-active substances include fatty acidtaurides, fatty acid N-methyltaurides, fatty acid isethionates,alkylphenylsulfonates, alkylnaphthalene-sulfonates, alkylphenolpolyglycol ether sulfates, fatty alcohol polyglycol ether sulfates,fatty acid amide polyglycol ether sulfates, alkylsulfosuccinamates,alkenylsuccinic monoesters, fatty alcohol polyglycol ethersulfosuccinates, alkanesulfonates, fatty acid glutamates,alkylsulfosuccinates, fatty acid sarcosides; fatty acids, examples beingpalmitic, stearic and oleic acid; soaps, examples being alkali metalsalts of fatty acids, naphthenic acids and resin acids, such as abieticacid, alkali-soluble resins, examples being rosin-modified maleateresins and condensation products based on cyanuric chloride, taurine,N,N′-diethylaminopropylamine and p-phenylenediamine. Particularpreference is given to resin soaps, i.e., alkali metal salts of resinacids.

Examples of suitable cation-active substances include quaternaryammonium salts, fatty amine alkoxylates, alkoxylated polyamines, fattyamine polyglycol ethers, fatty amines, diamines and polyamines derivedfrom fatty amines or fatty alcohols, and the alkoxylates of said amines,imidazolines derived from fatty acids, and salts of these cation-activesubstances, such as acetates, for example.

Examples of suitable nonionic substances include amine oxides, fattyalcohol polyglycol ethers, fatty acid polyglycol esters, betaines, suchas fatty acid amide N-propyl betaines, phosphoric esters of aliphaticand aromatic alcohols, fatty alcohols or fatty alcohol polyglycolethers, fatty acid amide ethoxylates, fatty alcohol-alkylene oxideadducts and alkylphenol polyglycol ethers.

By nonpigmentary dispersants are meant substances which in structuralterms are not derived from organic pigments. They are added asdispersants either during the actual preparation of pigments or else inmany cases during the incorporation of the pigments into the applicationmedia to be colored: for example, during the preparation of paints orprinting inks by dispersing of the pigments into the correspondingbinders. They may be polymeric substances, such as polyolefins,polyesters, polyethers, polyamides, polyimines, polyacrylates,polyisocyanates, block copolymers thereof, copolymers of thecorresponding monomers or polymers of one class modified with a fewmonomers of a different class. These polymeric substances carry polaranchor groups such as hydroxyl, amino, imino and ammonium groups,carboxylic acid and carboxylate groups, sulfonic acid and sulfonategroups or phosphonic acid and phosphonate groups, for example, and canalso be modified with aromatic nonpigmentary substances. Nonpigmentarydispersants may additionally be aromatic substances modified chemicallywith functional groups but not derived from organic pigments.Nonpigmentary dispersants of this kind are known to the skilled workerand in some cases are available commercially (e.g., Solsperse®, Avecia;Disperbyk®, Byk-Chemie, Efka®, Efka). A number of types will bementioned below as representatives; however, it is possible in principleto use any desired other substances described, examples beingcondensation products of isocyanates and alcohols, diols or polyols,amino alcohols or diamines or polyamines, polymers of hydroxy carboxylicacids, copolymers of olefin monomers or vinyl monomers and ethylenicallyunsaturated carboxylic acids and esters, urethane-containing polymers ofethylenically unsaturated monomers, urethane-modified polyesters,condensation products based on cyanuric halides, polymers containingnitroxyl compounds, polyesteramides, modified polyamines, modifiedacrylic polymers, dispersants with comblike structure formed frompolyesters and acrylic polymers, phosphoric esters, polymers derivedfrom triazine, modified polyethers, or dispersants derived fromaromatic, nonpigmentary substances. These base structures are in manycases modified further, by means for example of chemical reaction withfurther substances which carry functional groups, or by formation ofsalts.

By pigmentary dispersants are meant pigment dispersants which derivefrom an organic pigment as base structure and are prepared by chemicalmodification of said base structure; examples includesaccharine-containing pigment dispersants, piperidyl-containing pigmentdispersants, naphthalene- or perylene-derived pigment dispersants,pigment dispersants containing functional groups linked to the pigmentbase structure via a methylene group, pigment base structures modifiedchemically with polymers, pigment dispersants containing sulfo acidgroups, sulfonamide groups or sulfo acid ester groups, pigmentdispersants containing ether or thioether groups, or pigment dispersantscontaining carboxylic acid, carboxylic ester or carboxamide groups.

The pigment preparations of the present invention can be used aspreferably aqueous presscakes, but generally they are solid systems offree-flowing, pulverulent consistency or they are granules.

The warpage amelioration achievable according to the present inventionis believed to be due to a modification of the surface structure of thebase pigments via the pigment dispersant. There are a whole series ofcases where the efficacy of the pigment dispersant, and the quality ofthe pigment preparations produced thereby, are dependent on the time ofaddition of the pigment dispersant in the base pigment's manufacturingoperation. When two or more pigment dispersants are used, they may beadded at the same time or at different times or may be mixed beforebeing added.

The efficacy of the pigment dispersant may also depend on its particlesize and particle shape and also on the percentage of the pigmentsurface which is coatable. It may be preferable for the pigmentdispersant to be added to the base pigment only in the contemplatedapplication medium. The respective optimum concentration for the pigmentdispersant has to be determined in preliminary, exploratory tests, sincethe improvement in the properties of the base pigments does not alwayscorrelate linearly with the amount of pigment dispersant.

The pigment preparations of the present invention may be mixtures of oneor more, preferably 1, 2 or 3, base pigments with one or more,preferably 1 or 2, pigment dispersants.

The present invention also provides a process for producing a pigmentpreparation according to the present invention, said process comprisingthe pigment dispersant or dispersants and the base pigment or pigmentsbeing mixed with each other or being allowed to act on each other duringthe manufacturing operation. The manufacturing operation of adiketopyrrolopyrrole pigment comprises its synthesis, fine divisionand/or dispersion, for example by grinding, kneading or reprecipitating,if appropriate finishing, and also isolation as a presscake or as a drygranulate or powder. For example, the pigment dispersant may be addedbefore, during or after one of the customary processing steps such asfor example synthesis, fine-dividing operation, finishing, isolating,drying or pulverizing. For instance, addition at as early a stage as thesynthesis can lead to fine particles. It will be appreciated that thepigment dispersant may be also be added in subdivided portions atdifferent times.

When the pigment dispersant is added in the course of a fine-dividingoperation, it is added for example before or during salt kneading,before or during dry grinding of a crude pigment or before or during wetgrinding of a crude pigment. It will be similarly advantageous to addthe pigment dispersant before or after finishing of the base pigment inan aqueous or aqueous-organic medium at any desired pH or in an organicmedium.

The pigment dispersant may also be added to the preferably water-moistpigment presscake prior to drying and incorporated, in which case thepigment dispersant itself may likewise be present as a presscake. It isfurther possible to effect dry mixes of powder or granulate of thepigment dispersant with the powder or granulate of the base pigment, orto achieve the mixing in the course of a grinding or pulverization ofthe base pigment and of the pigment dispersant.

The pigment preparations of the present invention can be used forpigmentation of macromolecular organic materials of natural or syntheticorigin, for example of plastics, resins, coatings, paints orelectrophotographic toners and developers, and also of inks, includingprinting inks.

Examples of macromolecular organic materials which can be pigmented withthe pigment preparations mentioned include cellulose ethers andcellulose esters, such as ethylcellulose, nitrocellulose, celluloseacetate or cellulose butyrate, natural resins or synthetic resins, suchas addition-polymerization resins or condensation resins, examples beingamino resins, especially urea-formaldehyde and melamine-formaldehyderesins, alkyd resins, acrylic resins, phenolic resins, polycarbonates,polyolefins, such as polystyrene, polyvinyl chloride, polyethylene,polypropylene, polyacrylonitrile, polyacrylic esters, polyamides,polyurethanes or polyesters, rubber, casein, silicone and siliconeresins, individually or in mixtures.

It is irrelevant whether the aforementioned high molecular mass organiccompounds are in the form of plastic masses, melts or in the form ofspinning solutions, varnishes, paints or printing inks. Depending on theintended use it is found advantageous to utilize the pigments obtainedin accordance with the invention in the form of a blend or in the formof preparations or dispersions. Based on the high molecular mass organicmaterial to be pigmented, the pigment preparations of the invention areused in an amount of from 0.05 to 30% by weight, preferably from 0.1 to15% by weight.

The pigment preparations of the invention are also suitable as colorantsin electrophotographic toners and developers, such as one- ortwo-component powder toners (also called one- or two-componentdevelopers), magnetic toners, liquid toners, polymerization toners andspecialty toners, for example.

Typical toner binders are addition-polymerization resins, polyadditionresins and polycondensation resins, such as styrene, styrene-acrylate,styrene-butadiene, acrylate, polyester and phenol-epoxy resins,polysulfones, polyurethanes, individually or in combination, and alsopolyethylene and polypropylene, which may already include, or bemodified subsequently with, further ingredient additions, such as chargecontrol agents, waxes, or flow assistants.

The pigment preparations of the invention are further suited toapplication as colorants in powders and powder coating materials,particularly in triboelectrically or electrokinetically sprayable powdercoating materials which are employed to coat the surfaces of articlesmade, for example, from metal, wood, plastic, glass, ceramic, concrete,textile material, paper or rubber.

Resins used as powder coating resins are typically epoxy resins,carboxyl- and hydroxyl-containing polyester resins, polyurethane resinsand acrylic resins, together with customary curatives. Resincombinations also find use. Thus, for example, epoxy resins arefrequently employed in combination with carboxyl- andhydroxyl-containing polyester resins. Typical curative components(depending on the resin system) are, for example, acid anhydrides,imidazoles and also dicyandiamide and its derivatives, blockedisocyanates, bisacylurethanes, phenolic and melamine resins, triglycidylisocyanurates, oxazolines and dicarboxylic acids.

The pigment preparations of the invention are also suitable for use ascolorants in ink-jet inks, on both an aqueous and a non aqueous basis,and also in those inks which operate in accordance with the holt-meltprocess.

Ink-jet inks generally contain a total of from 0.5 to 15% by weight,preferably 1.5 to 8% by weight (calculated on a dry basis) of one ormore of the pigment preparations of the invention.

Microemulsion inks are based on organic solvents, water and, if desired,an additional hydrotropic substance (interface mediator).

Microemulsion inks generally contain from 0.5 to 15% by weight,preferably from 1.5 to 8% by weight, of one or more of the pigmentpreparations of the invention, from 5 to 99% by weight of water and from0.5 to 94.5% by weight of organic solvent and/or hydrotropic compound.

Solvent-based ink-jet inks contain preferably from 0.5 to 15% by weightof one or more of the pigment preparations of the invention, from 85 to99.5% by weight of organic solvent and/or hydrotropic compounds.

Hot-melt inks are generally based on waxes, fatty acids, fatty alcoholsor sulfonamides which are solid at room temperature and become liquid onheating, the preferred melting range being situated between about 60° C.and about 140° C. Hot-melt ink-jet inks are composed essentially, forexample, of from 20 to 90% by weight of waxes and from 1 to 10% byweight of one or more of the pigment preparations of the invention.Additionally it is possible for them to contain from 0 to 20% by weightof an additional polymer (as “dye dissolver”), from 0 to 5% by weight ofdispersing assistant, from 0 to 20% by weight of viscosity modifier,from 0 to 20% by weight of plasticizer, from 0 to 10% by weight of tackadditive, from 0 to 10% by weight of transparency stabilizer (whichprevents, for example, crystallization of the waxes) and from 0 to 2% byweight of antioxidant. Typical additives and auxiliaries are describedfor example in U.S. Pat. No. 5,560,760.

Additionally the pigments prepared in accordance with the invention arealso suitable for use as colorants for color filters, for both additiveand subtractive color generation, and also for electronic inks.

The pigment preparations of the present invention are useful forcalibration of partly crystalline plastics. The present inventionaccordingly further provides for the use of the above-described pigmentpreparation of the present invention for warpage-free mass pigmentationof partly crystalline plastics.

As used herein, the term “warpage-free” is to be understood as meaning adegree of warpage which is distinctly reduced compared with theuntreated pigment.

Partly crystalline plastics is to be understood as referring to thosewhich solidify to form small crystalline nuclei or aggregates, includingthose which do so only in the presence of nucleating agents (organicpigments for example). Partly crystalline plastics are generallythermoplastic macromolecular organic materials having a molecular weight(M_(w)) of 10⁴ to 10⁸ g/mol, preferably 10⁵ to 10⁷ g/mol, and acrystallinity (X_(c)) of 10 to 99.9%, preferably of 40 to 99% and morepreferably of 80 to 99%. Preferred partly crystalline plastics arehomopolymers, block or random copolymers and terpolymers of ethylene,propylene, butylene, styrene and/or divinylbenzene, especiallypolyolefins, such as polyethylene (HDPE, MDPE, LDPE), polypropylene,especially high density polyethylene (HDPE), also polystyrene, PVC,polyesters, such as polyethylene terephthalate, and polyamides, such asnylon 6 and nylon 66, and thermoplastic ionomers. The partly crystallineplastics may further comprise additives in customary amounts, examplesbeing stabilizers, optical brighteners, fillers and lubricants.

When used for coloration of partly crystalline plastics, thephthalocyanine pigment treated according to the present invention willadvantageously be used in an amount of 0.01% to 5% by weight andpreferably 0.05% to 1% by weight, based on the plastic. The colorationstep can be carried out according to customary methods, as by extrusionfor example.

The influence on the warpage propensity of polyolefin by the pigmentproduced according to the present invention is tested on aready-produced injection molding in the form of a plaque. After aging,the dimensions of the plaque (length, width) are measured and the degreeof warpage is determined.

The pigment preparations of the present invention possess an amelioratedDIN EN 20105-A03 bleed resistance and an enhanced DIN EN 12877 thermalstability compared with mixtures described in EP 952 183.

In the examples which follow percentages are by weight, unless otherwisestated.

EXAMPLE 1

13.5 parts of P.R.254 prepared by the process disclosed in EP 94 911 aresuspended in a mixture of 150 parts of water and 150 parts of tert-amylalcohol. Addition of 1.5 parts of pigment dispersant of the formula (X)

prepared according to Example 4, is followed by adjustment to pH 5 withacetic acid and stirring at 85° C. for 10 hours. The amyl alcohol isremoved by steam distillation, the suspension is filtered, the presscakeis washed with water, dried at 80° C. and ground to give 13.6 parts ofpigment preparation.

The pigment preparation is used to pigment polyethylene plaques (600 gof ®Novolen and 0.6 g of pigment preparation) and warpage is determined.

Method: Shrinkage testing of organic pigments in injection-moldedpolyethylene. A rectangular plaque is molded with film gate and thedimensions 60 by 60 mm. Evaluation is by measurement along and acrossthe direction of molding. For each pigment tested 10 moldings wereproduced and measured out, the respective average value being employed.The control used is 10 moldings from nonpigmented plastic. It is veryimportant in this connection that this material experience exactly thesame processing history as the pigmented system.

The polyethylene plaques pigmented with the pigment preparation of thepresent invention have a distinctly lower warpage value than the aboveP.R.254 without pigment dispersant.

EXAMPLE 2 Comparative

When P.R.254, prepared by the process disclosed in EP 94911, is treatedwith the DE 19958181 pigment dispersant, prepared according to Example10a, the pigment preparation is associated with a significantly greaterwarpage than the inventive pigment preparation of Example 1.

EXAMPLE 3 Comparative

The P.R 254 Chromophtal Red 2028 additized with the pigment dispersantof EP 952183 has a lower DIN EN 20105-A03 bleed resistance at 4 than theinventive pigment preparation of Example 1, which has a bleed resistanceof 4–5.

EXAMPLE 4

50 parts of a commercially available P.R.255 are introduced into 500parts of chlorosulfonic acid and stirred at 80° C. for 3 hours. Aftercooling to 50° C., 53.8 parts of thionyl chloride are added dropwisebefore stirring at 60° C. for 2 hours. After cooling to roomtemperature, the mixture is poured onto a mixture of 400 parts of waterand 800 parts of ice, the suspension is filtered, the presscake iswashed with ice-water and suspended in 1000 parts of water. This isfollowed by stirring under reflux for 3 hours, addition of 300 parts of33% hydrochloric acid at 60° C., cooling to 15° C., filtration andwashing with 10% hydrochloric acid. 69 parts of the presscake areintroduced into 700 parts of toluene and the water is distilled off. At50° C., 26.9 parts of thionyl chloride are added dropwise over 30minutes. This is followed by stirring at 55° C. for 2 hours beforeexcess thionyl chloride is distilled off at 50° C. under reducedpressure. Then 83.8 parts of dioctylamine are added before stirring at60° C. for 2 hours. The suspension is filtered, washed with toluene,ethanol and water and the presscake is dried at 80° C. to give 32.4parts of pigment dispersant of the formula (X).

EXAMPLE 5

6.8 parts of DPP derivative of the formula (XI)

are introduced into 100 parts of glacial acetic acid and oxidized at 10°C. by dropwise addition of 4.9 parts of 35% hydrogen peroxide. Thedropwise addition is followed by stirring at room temperature for 4hours before the mixture is poured onto 120 parts of ice-water. Theproduct is filtered, washed and dried to leave 5.9 parts of pigmentdispersant of the formula (XII).

EXAMPLE 6

95 parts of P.R.254 are mixed with 5 parts of pigment dispersant of theformula (XII), prepared as per Example 5. Strong colorations having aclean hue are obtained in polyethylene. The warpage of polyethyleneplaques pigmented with this mixture is distinctly reduced.

EXAMPLE 7

3.46 parts of DPP derivative of the formula (XII) are introduced into265 parts of methylene chloride and cooled down to 0° C. A solution of2.73 parts of 70% 3-chloroperbenzoic acid in 93 parts of methylenechloride is added dropwise at 0° C. over 20 minutes. This is followed bystirring at room temperature for 5 hours, two washes with 10% aqueoussodium sulfide solution and distillative removal of methylene chlorideto leave 1.8 parts of pigment dispersant of the formula (XIII).

EXAMPLE 8

95 parts of P.R.254 are mixed with 5 parts of pigment dispersantprepared as per Example 7. Strong colorations having a clean hue areobtained in polyethylene. The warpage of polyethylene plaques pigmentedwith this mixture is distinctly reduced.

EXAMPLE 9a

40 parts of P.R.255 are added to 160 parts of 20% oleum before stirringat 5 to 10° C. for 15 min. 120 parts of chlorosulfonic acid are addeddropwise before stirring at 10° C. for 6 hours. The mixture is pouredonto 1000 parts of ice-water, the sulfochloride is filtered off withsuction, washed with water and then with acetone and dried.

EXAMPLE 9b

A mixture of 50.5 parts of a 30% aqueous presscake of P.R.254, 7 partsof water, 42.5 parts of tert-amyl alcohol and 0.79 parts ofsulfochloride prepared according to Example 9a is adjusted to pH 12 with33% aqueous sodium hydroxide solution and then stirred under reflux for30 min to hydrolyze the sulfochloride to sulfonic acid. Then 5.8 partsof 30% aqueous solution of cetyltrimethylammonium chloride are addedbefore stirring under reflux for a further 30 min. After pH 4.5 has beenset with acetic acid, the mixture is stirred under reflux for another 1hour. The pigment preparation consisting of P.R.254 and the pigmentdispersant which comes within the formula (VII) and consists of the saltof the deprotonated sulfonic acid of P.R.255 and thecetyltrimethylammonium used is filtered off with suction, washed anddried.

EXAMPLE 9c

The polyethylene plaques colored with the pigment preparation producedaccording to Example 9b show distinctly reduced warpage.

1. A pigment preparation comprising a) at least one base pigment,wherein the at least one base pigment is at least onediketopyrrolopyrrole pigment of the formula (V),

where  R²⁰, R²¹, R²² and R²³ are independently hydrogen, halogen,C₁–C₄-alkyl, C₁–C₄-alkoxy, cyano or phenyl; and b) at least one pigmentdispersant of the formula (I),

where  R³¹ is a radical of the formula (VI), (VIII) or (IX), R³² is aradical of the formula (VII), s or t is a number from 0.1 to 4.0

n is a number from 0 to 2, with the proviso that n is 0 when R³¹ is aradical of the formula (VIII) or (IX), E⁺ is H⁺ or the equivalentM^(m+)/m of a metal cation M^(m+) from the 1st to 5th main group or fromthe 1st, 2nd or 4th to 8th transition group of the periodic table ofchemical elements, m being one of 1, 2 or 3; an ammonium ion N^(+R)⁹R¹⁰R¹¹R¹², wherein R⁹, R¹⁰, R¹¹ and R¹² are each independently ahydrogen atom, C₁–C₃₀-alkyl, C₂–C₃₀-alkenyl, C₅–C₃₀-cycloalkyl, phenyl,(C₁–C₈)-alkylphenyl, (C₁–C₄)-alkylenephenyl, or a (poly)alkyleneoxygroup of the formula —[CH(R⁸⁰)—CH(R⁸⁰)—O]_(k)—H, where k is a numberfrom 1 to 30 and each R⁸⁰ is independently hydrogen, C₁–C₄-alkyl or,when k is >1, a combination thereof; and wherein the C₁-C30-alkyl,C₂–C₃₀-alkenyl, C₅–C₃₀-cycloalkyl, phenyl or (C₁–C₈)-alkylphenyl areoptionally substituted by amino, hydroxyl and/or carboxyl; or thesubstituents R⁹ and R¹⁰ combine with the quaternary nitrogen atom toform a five-, six- or seven-membered saturated ring system optionallycontaining additional heteroatoms selected from the group consisting ofO, S and N; or the substituents R⁹, R¹⁰ and R¹¹ combine with thequaternary nitrogen atom to form a five-, six- or seven-memberedaromatic ring system optionally containing additional heteroatomsselected from the group consisting of O, S and N and optionally, hasadditional rings fused thereon; or wherein E⁺ is an ammonium ion of theformula (Ic)

wherein R¹⁵, R¹⁶, R¹⁷ and R¹⁸ are independently hydrogen or a(poly)alkyleneoxy group of the formula —[CH(R⁸⁰)—CH(R⁸⁰)O]_(k)—H, wherek is a number from 1 to 30 and each R⁸⁰ is independently hydrogen,C₁–C₄-alkyl or, when k>1, a combination thereof; q is a number from 1 to10; p is a number from 1 to 5, subject to the proviso that p≦q+1; T is abranched or unbranched C₂–C₆-alkylene radical; or when q is ≦1 T isoptionally a combination of branched or unbranched C₂–C₆-alkyleneradicals; Z¹ and Z² are the same or different and are hydrogen orC₁–C₃₀-alkyl linear or branched C₁–C₃₀-alkenyl linear or branched,wherein the C₁–C₃₀-alkyl and C₁–C₃₀-alkenyl are unsubstituted orhalogen, hydroxyl, hydroxycarbonyl or C₁–C₆-alkoxy-substituted, whereinthe C₁–C₃₀alkenyl radical is optionally singly or multiply unsaturated,with the proviso that Z¹ and Z² are not both hydrogen; and Q is aradical of a diketopyrrolopyrrole compound of the formula (Ia)

where R²⁴, R²⁵, R²⁶ and R²⁷ are independently hydrogen, halogen,(C₁–C₄)-alkyl, (C₁–C₄)-alkoxy or cyano.
 2. The pigment preparationaccording to claim 1 wherein s or t is 0.2 to 3.0.
 3. The pigmentpreparation according to claim 1 wherein Z¹ and Z² are the same ordifferent and are each C₂–C₁₆-alkyl, R²⁴ and R²⁶ are each hydrogen andR²⁵ and R²⁷ are each hydrogen, methyl, tert-butyl, chlorine or cyano. 4.The pigment preparation according to claim 1, wherein the base pigmentof the formula (V) has R²¹ and R²³ both hydrogen and R²⁰ and R²² thesame or different and each hydrogen, methyl, tert-butyl, chlorine, cyanoor phenyl.
 5. The pigment preparation according to claim 1, wherein thebase pigment is C.I. Pigment Orange 71, 73, 81, C.I. Pigment Red 254,255, 264, 270 or
 272. 6. The pigment preparation according to claim 1,consisting essentially of a) 50% to 99.9% by weight of at least one basepigment, b) 0.1% to 25% by weight of at least one pigment dispersant,and c) 0% to 25% by weight of at least one auxiliary, the fractions ofthe respective components being based on the 100% weight of thepreparation.
 7. The pigment preparation according to claim 1, wherein nis 0 to 0.5.
 8. A process for producing a pigment preparation accordingto claim 1, comprising the step of adding the at least one pigmentdispersant to the at least one base pigment during the manufacture ofthe at least base pigment, wherein the manufacture of the at least onepigment includes: synthesizing the at least one base pigment, dividingthe at least one base pigment, dispersing the at least one base pigment,and isolating the at least one pigment.
 9. The process according toclaim 8, wherein the manufacture of the at least one pigment furthercomprises finishing the at least one base pigment.
 10. The processaccording to claim 8, wherein the isolating step of the manufacture ofthe at least one base pigment further comprises forming the at least onebase pigment into a presscake, dry granulate or powder.
 11. A pigmentedcomposition comprising a pigment preparation according to claim
 1. 12.The pigmented composition according to claim 11, wherein pigmentedcomposition is selected from the group consisting of plastics, resins,coatings, paints electrophotographic toners electrophotographicdevelopers and inks.
 13. The pigmented composition according to claim11, wherein the pigmented composition is a printing ink.
 14. A processfor warpage-free mass pigmentation of a partly crystalline plasticcomprising the step of adding a pigment preparation according to claim 1to the partly crystalline plastic during the manufacture of the partlycrystalline plastic.
 15. The process according to claim 14 wherein thepartly crystalline plastic is a homopolymer, block copolymer, randomcopolymer or terpolymer of ethylene, propylene, butylene, styrene,divinylbenzene or mixtures thereof.
 16. The process according to claim14 wherein the partly crystalline plastic is a polyethylene,polypropylene, polystyrene, PVC, polyester, polyamide or a thermoplasticionomer.
 17. The process according to claim 14, wherein the partlycrystalline plastic is HDPE, MDPE, LDPE, polyethylene terephthalate,nylon 6 or nylon
 66. 18. A partly crystalline plastic made in accordancewith the process of claim 15.